Positron Emission Computed Tomography (PET) technology has been widely applied to biomedical research fields such as tumor early detection, drug screening and the like. By injecting a radioactive tracer into a subject's body and detecting photons produced by an annihilation event outside the subject's body with a PET device, the PET technology may be used to obtain spatial distribution of the tracer inside the subject's body according to data collected by the PET device, thereby indirectly obtaining physiological metabolism information of the subject. A γ-photon produced by an annihilation event may be detected by a crystal of a PET device, and data collected by the PET device may include true coincidence data, scattering coincidence data and random coincidence data. When reconstructing a PET image with the collected data, the scattering coincidence data and the random coincidence data may be removed from the collected data. For example, the scattering coincidence data may be removed according to a scattering correction factor and the random coincidence data may be removed according to a random correction factor. However, since the scattering coincidence data is derived from two photons which are produced by one annihilation event and one of the two photons deflects in angle, directly removing the scattering coincidence data may lead to loss of a part of the collected data. In this way, the collected coincidence data may not be fully utilized. Further, the process of removing scattering coincidence data may increase the amount of calculation and reduce the efficiency of image reconstruction.
NEUSOFT MEDICAL SYSTEMS CO., LTD. (NMS), founded in 1998 with its world headquarters in China, is a leading supplier of medical equipment, medical IT solutions, and healthcare services. NMS supplies medical equipment with a wide portfolio, including CT, Magnetic Resonance Imaging (MRI), digital X-ray machine, ultrasound, Positron Emission Tomography (PET), Linear Accelerator (LINAC), and biochemistry analyser. Currently, NMS' products are exported to over 60 countries and regions around the globe, serving more than 5,000 renowned customers. NMS's latest successful developments, such as 128 Multi-Slice CT Scanner System, Superconducting MRI, LINAC, and PET products, have led China to become a global high-end medical equipment producer. As an integrated supplier with extensive experience in large medical equipment, NMS has been committed to the study of avoiding secondary potential harm caused by excessive X-ray irradiation to the subject during the CT scanning process.